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Rollup merge of #115536 - RalfJung:interpreter-privacy, r=oli-obk

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interpret: make MemPlace, Place, Operand types private to the interpreter

Outside the interpreter, only the typed versions should be used.
This commit is contained in:
Matthias Krüger 2023-09-05 15:16:50 +02:00 • committed by GitHub
commit 09974dfc69
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GPG key ID: 4AEE18F83AFDEB23
41 changed files with 417 additions and 338 deletions
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24
compiler/rustc_mir_transform/src/const_prop.rs
View file

@ -22,8 +22,7 @@ use rustc_target::spec::abi::Abi as CallAbi;
use crate::MirPass;
use rustc_const_eval::interpret::{
self, compile_time_machine, AllocId, ConstAllocation, ConstValue, FnArg, Frame, ImmTy,
Immediate, InterpCx, InterpResult, LocalValue, MemoryKind, OpTy, PlaceTy, Pointer, Scalar,
StackPopCleanup,
Immediate, InterpCx, InterpResult, MemoryKind, OpTy, PlaceTy, Pointer, Scalar, StackPopCleanup,
};
/// The maximum number of bytes that we'll allocate space for a local or the return value.
@ -225,11 +224,11 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for ConstPropMachine<'mir, 'tcx>
throw_machine_stop_str!("pointer arithmetic or comparisons aren't supported in ConstProp")
}
fn access_local_mut<'a>(
fn before_access_local_mut<'a>(
ecx: &'a mut InterpCx<'mir, 'tcx, Self>,
frame: usize,
local: Local,
) -> InterpResult<'tcx, &'a mut interpret::Operand<Self::Provenance>> {
) -> InterpResult<'tcx> {
assert_eq!(frame, 0);
match ecx.machine.can_const_prop[local] {
ConstPropMode::NoPropagation => {
@ -242,7 +241,7 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for ConstPropMachine<'mir, 'tcx>
}
ConstPropMode::FullConstProp => {}
}
ecx.machine.stack[frame].locals[local].access_mut()
Ok(())
}
fn before_access_global(
@ -382,8 +381,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
// mark those as live... We rely on `local_to_place`/`local_to_op` in the interpreter
// stopping us before those unsized immediates can cause issues deeper in the
// interpreter.
ecx.frame_mut().locals[local].value =
LocalValue::Live(interpret::Operand::Immediate(Immediate::Uninit));
ecx.frame_mut().locals[local].make_live_uninit();
}
ConstPropagator { ecx, tcx, param_env, local_decls: &dummy_body.local_decls }
@ -392,7 +390,11 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
fn get_const(&self, place: Place<'tcx>) -> Option<OpTy<'tcx>> {
let op = match self.ecx.eval_place_to_op(place, None) {
Ok(op) => {
if matches!(*op, interpret::Operand::Immediate(Immediate::Uninit)) {
if op
.as_mplace_or_imm()
.right()
.is_some_and(|imm| matches!(*imm, Immediate::Uninit))
{
// Make sure nobody accidentally uses this value.
return None;
}
@ -415,8 +417,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
/// Remove `local` from the pool of `Locals`. Allows writing to them,
/// but not reading from them anymore.
fn remove_const(ecx: &mut InterpCx<'mir, 'tcx, ConstPropMachine<'mir, 'tcx>>, local: Local) {
ecx.frame_mut().locals[local].value =
LocalValue::Live(interpret::Operand::Immediate(interpret::Immediate::Uninit));
ecx.frame_mut().locals[local].make_live_uninit();
ecx.machine.written_only_inside_own_block_locals.remove(&local);
}
@ -743,7 +744,8 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
) -> Option<PlaceElem<'tcx>> {
if let PlaceElem::Index(local) = elem
&& let Some(value) = self.get_const(local.into())
&& let interpret::Operand::Immediate(Immediate::Scalar(scalar)) = *value
&& let Some(imm) = value.as_mplace_or_imm().right()
&& let Immediate::Scalar(scalar) = *imm
&& let Ok(offset) = scalar.to_target_usize(&self.tcx)
&& let Some(min_length) = offset.checked_add(1)
{

20
compiler/rustc_mir_transform/src/const_prop_lint.rs
View file

@ -7,7 +7,7 @@ use either::Left;
use rustc_const_eval::interpret::Immediate;
use rustc_const_eval::interpret::{
self, InterpCx, InterpResult, LocalValue, MemoryKind, OpTy, Scalar, StackPopCleanup,
InterpCx, InterpResult, MemoryKind, OpTy, Scalar, StackPopCleanup,
};
use rustc_const_eval::ReportErrorExt;
use rustc_hir::def::DefKind;
@ -212,8 +212,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
// mark those as live... We rely on `local_to_place`/`local_to_op` in the interpreter
// stopping us before those unsized immediates can cause issues deeper in the
// interpreter.
ecx.frame_mut().locals[local].value =
LocalValue::Live(interpret::Operand::Immediate(Immediate::Uninit));
ecx.frame_mut().locals[local].make_live_uninit();
}
ConstPropagator {
@ -236,7 +235,11 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
fn get_const(&self, place: Place<'tcx>) -> Option<OpTy<'tcx>> {
let op = match self.ecx.eval_place_to_op(place, None) {
Ok(op) => {
if matches!(*op, interpret::Operand::Immediate(Immediate::Uninit)) {
if op
.as_mplace_or_imm()
.right()
.is_some_and(|imm| matches!(*imm, Immediate::Uninit))
{
// Make sure nobody accidentally uses this value.
return None;
}
@ -259,8 +262,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
/// Remove `local` from the pool of `Locals`. Allows writing to them,
/// but not reading from them anymore.
fn remove_const(ecx: &mut InterpCx<'mir, 'tcx, ConstPropMachine<'mir, 'tcx>>, local: Local) {
ecx.frame_mut().locals[local].value =
LocalValue::Live(interpret::Operand::Immediate(interpret::Immediate::Uninit));
ecx.frame_mut().locals[local].make_live_uninit();
ecx.machine.written_only_inside_own_block_locals.remove(&local);
}
@ -656,12 +658,12 @@ impl<'tcx> Visitor<'tcx> for ConstPropagator<'_, 'tcx> {
}
StatementKind::StorageLive(local) => {
let frame = self.ecx.frame_mut();
frame.locals[local].value =
LocalValue::Live(interpret::Operand::Immediate(interpret::Immediate::Uninit));
frame.locals[local].make_live_uninit();
}
StatementKind::StorageDead(local) => {
let frame = self.ecx.frame_mut();
frame.locals[local].value = LocalValue::Dead;
// We don't actually track liveness, so the local remains live. But forget its value.
frame.locals[local].make_live_uninit();
}
_ => {}
}